We last wrote about COVID-19 symptoms at the end of April. Since then, the Centers for Disease Control and Prevention (CDC) has added several new symptoms of possible infection: congestion, runny nose, nausea or vomiting, and diarrhea. Symptoms previously listed include fever or chills, cough, shortness of breath or difficulty breathing, fatigue, muscle or body aches, headache, loss of taste or smell, and sore throat.
The most common symptoms of the illness remain some combination of fever, loss of taste or smell, dry cough, and fatigue. Of these, anosmia — the loss of sense of smell that is also often accompanied by a loss of taste — has emerged as one of the most predictive. One study of 961 healthcare workers who were tested for COVID-19 showed that anosmia was the symptom most often associated with a positive PCR test. Similarly, a European study done earlier this year found that 87 percent of more than 2,000 patients reported losing their sense of smell while more than half reported a loss of the ability to taste.
Fever, on the other hand, while common, may not be the benchmark indicator it was once thought to be. For example, one study showed that only 31 percent of patients sick enough to be hospitalized for COVID-19 at New York’s largest hospital system had a fever at the time they were admitted. Another study, involving 443 COVID-positive nursing home residents, found that only 26.6 percent of these patients met the fever threshold of 100.4°F (38.0°C) during the course of the study.
The virus usually enters the body through the nose, which is lined with the ACE2 (angiotensin-converting enzyme 2) receptors that serve as the virus’s entryway to the cells. But ACE2 receptors are found throughout the body — on cells in the lungs, blood vessels, intestines, and other organs — so perhaps it’s no surprise that the virus can have wide-ranging effects outside of the respiratory system. Gastrointestinal symptoms are now known to be common and may be the only, or primary, symptoms for some patients. Severely ill patients can experience life-threatening blood clots. And, though not on the CDC’s symptom list at this time, researchers and the World Health Organization (WHO) have reported the possibility of dermatological symptoms, including rashes and discolorations of fingers and toes.
As researchers continue to study the virus and clinicians continue to observe infected patients, it is possible that other symptoms will be added to the CDC’s list.
In the meantime, if you are a member of the MIT community and are experiencing symptoms of COVID-19, call MIT Medical’s COVID-19 hotline at 617-253-4865. We can tell you if you need to be tested. CDC recommendations continue to stress that “emergency warning signs” necessitating immediate medical attention — meaning a call to 911 — include trouble breathing, persistent pain or pressure in the chest, confusion or partial loss of consciousness, and bluish lips or face.